Page 23 preliminary 136 



working ground will be at a minimum. This also applies to the selection of harbors 

 and anchorages for the ship, although its safety is the first consideration. 



In isolated areas, where a shore party is supplied and provisioned from the survey 

 ship, it is essential that there be means of communication between them. In recent 

 years all such shore parties have been equipped with a sending and receiving radiophone. 

 This has proved very effective since it enables the chief of the subparty to report to the 

 Chief of Party on his daily progress, on the status of his supplies and provisions, and 

 on any accident, such as damage to floating equipment or injury to personnel, and on 

 any sickness requiring transfer of personnel to the ship for medical attention. It also 

 permits plans to be made in advance for moving the camp if that is to be done with the 

 aid of the ship. 



136. Project Layout 



To plan and carry out effectively and systematically extensive combined operations 

 it will generally be necessary to lay out on a chart of suitable scale the limits of the proj- 

 ect, the limits of previously surveyed areas with which the instructions specify a junc- 

 tion, the principal control stations, and any other data which may be of importance. 

 If the area is an unsurveyed one and the only existing chart is of small scale and of a 

 reconnaissance nature, it may be necessary to make this layout on a reconnaissance 

 sketch especially constructed therefor. 



1361. Sheet Layout 



Since different scales are generally necessary for the surveys of different parts of 

 an area, and since the size of a sheet is limited, more than one sheet will usually be 

 required for the survey of an extensive area. In order that these sheets may be planned 

 practicably and economically, a sheet layout should be made on a chart of suitable 

 scale, or in an unsurveyed area on a reconnaissance sketch, on which are outlined all 

 or a part of the sheets required to cover the area. (See fig. 2.) 



Each hydrographic sheet should be laid out in such a manner that it will include 

 as large a water area as practicable, at the same time providing for adequate overlap 

 with adjacent sheets and ensuring that all of the required control stations will be included. 

 Skewed projections must be avoided if it is practicable to do so (see 1362). The over- 

 lap of adjacent sheets should generally be no more than is required to provide for a 

 suitable junction of adjacent surveys and to mclude the necessary control stations 

 (see 123). Hydrography must not be extended to the offshore limits of a sheet when 

 it can be more strongly controlled on an adjoining offshore sheet; neither should it be 

 extended parallel to the shore to the extreme limits of a sheet where it can be more 

 strongly controlled on an adjacent alongshore sheet. In these cases the extent of the 

 overlap should be sufficient to provide hydrography controlled with equal strength on 

 both sheets. 



If the project is for the resurvey of an area fairly well represented on existing charts 

 it may be practicable, at the start of the project, to lay out sheets covering the entire 

 area. If the project is for the survey of a comparatively unknown area, it may be 

 preferable to extend the sheet layout from time to time, as more detailed information 

 relative to the area becomes available. 



A convenient method for making this layout is to construct on tracing cloth an 

 outline of each appropriately sized sheet according to the scale of the published chart 

 on which the layout is to be made. The tracing cloth containing the limits may then 



